1. Field of the Invention
The present invention relates to a coupling element and to a coupling intended for removably joining two pipes.
2. Brief Description of the Related Art
EP-A-1 164 327 teaches the connecting of two elements of a coupling using locking ramps with over-travel formed in a ring of a first element and intended to accept radially projecting lugs of the second element. The two elements of the coupling comprise shut-off valves associated with springs, which tend to push the elements apart. The locking is obtained by pushing the elements closer together against the action of the valve springs until an over-travel zone is reached in which the valve springs push the lugs of the second elements into notches. In this device, the lugs are locked exclusively by the valve springs. As a result, there is a risk that the elements will become disconnected if the pressure in the fluid circuits coupled drops and there is at the same time a relative rotation of the elements, for example under the effect of vibrations, tending to cause the two elements to move closer together and to drive the lugs into the over-travel zones of the locking ramps, in the unlocking direction.
FR-A-1 580 284 also teaches the coupling of male and female elements using a slit ring mounted with the possibility of rotating about a body of the female element. The slit ring comprises two juxtaposed series of slits, a first series of slits being intended to accept radially projecting tenons of the male element, while the second series of slits is intended to accept internal lugs of an outer ring that fits over the slit ring. The two series of slits are arranged in such a way that the slit ring is made to rotate about the body of the female element when the male and female elements are moved axially closer together. By rotating the slit ring it is possible simultaneously to lock the tenons of the male element in circumferential notches of the first series of slits and the internal lugs of the outer ring in inclined notches of the second series of slits. In this device, introducing the tenons of the male element into the first series of slits entails aligning these slits with axial slits in the body of the female element. Now, as the slit ring is mounted with freedom to rotate about the body of the female element, these slits are liable to become shifted relative to one another. They can be aligned by exerting a backward force on the outer ring beforehand, against the action of a spring. The locking of the male and female elements is therefore not automatic.
Elsewhere, U.S. Pat. No. 5,253,716 describes a female coupling element comprising two superposed rings including an inner ring welded to a body of the female element and an outer ring able to move axially with respect to the inner ring. The inner ring comprises slits for accommodating radially projecting lugs of a male element able to be pushed into the female element, each lug being designed to be secured in a slit of the inner ring by means of a corresponding semicircular slot in the outer ring. In this device, connecting the male and female elements entails moving the outer ring back with respect to the inner ring and rotating the male element with respect to the female element in order to cause the lugs of the male element to travel along the slits in the inner ring. A device such as this does not allow the coupling elements to be locked automatically in a single movement on the part of an operator.